mcmd is the MySQL Cluster Manager agent program. Invoking this executable starts the MySQL Cluster Manager Agent, to which you can connect using the mcm client (see Section 4.3, “Starting the MySQL Cluster Manager Client” and Chapter 5, MySQL Cluster Manager Client Commands for more information).
You can modify the behavior of the agent by specifying one or more of the options discussed in this section. Depending on the option of interest, there are up to three ways to set it:
Include the option directly on the command line when invoking mcmd. This can be done for all options that has Yes under the Cmd-Line column in Table 4.1 MySQL Cluster Manager Agent (mcmd) Option Summary. Some options can only be specified by this method on the command line (for example,
--config
and--bootstrap
).When specifying an agent configuration option on the command line using this method, the name of the option is prefixed with two leading dash characters (
--
); for example,--mcmd-user=johndoe
. See the Command-Line Format for each option given in the option description table.Include the option in the agent configuration file. This can be done for all options that has Yes under the Option File column in Table 4.1 MySQL Cluster Manager Agent (mcmd) Option Summary. These rules apply:
The name of the option should not be prefixed with dashes, or any other characters.
Any hyphens in the option names should be changed to underscores.
The format of the configuration file follows that of the MySQL Router configuration file; see Configuration File Syntax for an explanation of the file format. An option must be specified in the correct section in the configuration file; see Table 4.1, “MySQL Cluster Manager Agent (mcmd) Option Summary” for which section each option belongs to.
Each option must be specified on a separate line. You can comment out a line by inserting a leading hash character (
#
).
For MySQL Cluster Manager 8.0.28 and later: Any options configurable in the configuration file (i.e., by method 2 above), with the exception of
mcmd_password
, can be set or overridden at the mcmd command line by specifying the option in the format of--
, wheresection_name
.option
=value
section_name
is name of the section in the configuration file that the option belongs to. For example,--mcmd.bind_port=12345
and--logger.level=DEBUG
.
The following table contains a summary of agent options that are read on startup by mcmd. More detailed information about each of these options can be found in the option descriptions.
Table 4.1 MySQL Cluster Manager Agent (mcmd) Option Summary
Name | Cmd-Line | Option File | Configuration File Section |
---|---|---|---|
bind_address | - | Yes | mcmd |
bind-port | Deprecated | Yes | mcmd |
bootstrap | Yes | - | - |
config | Yes | - | - |
copy-port | Deprecated | Yes | mcmd |
core-file | Yes | - | - |
data-folder | Yes | Yes | DEFAULT |
extra-config | Yes | - | - |
filename | - | Yes | logger , syslog , filelog ,
eventlog |
help | Yes | - | - |
initial | Yes | - | - |
level | - | Yes | logger |
logging_folder | - | Yes | DEFAULT |
max_total_connections | - | Yes | DEFAULT |
mcmd_password | - | Yes | mcmd |
mcmd-user | Deprecated | Yes | mcmd |
pid-file | Yes | Yes | DEFAULT |
sinks | - | Yes | DEFAULT |
unknown_config_option | - | Yes | DEFAULT |
version | Yes | - | - |
xcom-port | Deprecated | Yes | mcmd |
MySQL Cluster Manager Agent (mcmd
) Option Descriptions
The following list contains descriptions of each configuration option available for use with mcmd, including allowed and default values. Options with their Type unmentioned need only be specified in order to take effect— you should not try to set a value for them.
-
Type String Default Value 127.0.0.1
Specify the address for MySQL Cluster Manager client connections. Binding to a specific IPv4 or IPv6 address ensures that mcmd is not starting on a network interface controller (NIC) on which nothing is allowed to execute.
It is not possible to specify more than one bind address. Using
::
binds all network interfaces (IPs) on the host.When set in the configuration file, the option should be put inside the
[mcmd]
section. -
Command-Line Format --bind-port=#
(≤ 8.0.30)Type Numeric Default Value 1862
Minimum Value 1
Maximum Value 65535
Specify the port used by MySQL Cluster Manager client connections. Any valid TC/IP port number can be used. Normally, there is no need to change it from the default value (1862).
MySQL Cluster Manager 8.0.30 and later: The command-line format
--bind-port
for this option has been deprecated. Use--mcmd.bind-port
instead on the command line (which takes precedence over all other ways to specify the option), or specify the option in the configuration file (both methods take precedence over the deprecated command-line format). -
Command-Line Format --bootstrap
Start the agent with default configuration values, create a default one-machine cluster named
mycluster
in a site namedmysite
, and start it. This option works only if no sites have been created yet. -
Command-Line Format --config=file_name
Type File name Default Value mcmd.conf, in the MCM installation directory
Set the file from which to read configuration options.
mcmd.conf
in the installation directory of MySQL Cluster Manager is the first default location mcmd looks for the file. See Section 3.4, “MySQL Cluster Manager Configuration File” for more information. -
Command-Line Format --copy-port=#
(≤ 8.0.30)Type Numeric Default Value 0
Minimum Value 0
Maximum Value 65535
Allows you to specify the port for file copy operations. The default is 0.
For release 8.0.30 and later: The command-line format of
--copy-port
has been deprecated. Use the format--mcmd.copy-port
instead (which takes precedence over all other ways to specify the option), or specify the option in the configuration file (both methods take precedence over the deprecated command-line format). -
Command-Line Format --core-file[=value]
Introduced 8.0.32 Type Boolean Default Value 1
Valid Values 1
(Write a core file)0
(Do not write a core file)Write a core file to the location where mcmd was started (or to another core dump location as specified by the operating system) when mcmd quits unexpectedly. The default value is 1.
--data-folder=
,dir_name
-d
dir_name
Command-Line Format --data-folder=dir_name
Type Directory name Default Value mcm_data in the parent directory of the MCM installation directory
Set the location of the agent repository, which contains collections of MySQL Cluster Manager data files and MySQL NDB Cluster configuration and data files. The value must be a valid absolute path.
The default location is
mcm_data
in the parent directory of the MySQL Cluster Manager installation directory. If you change the default, you should use a standard location external to the MySQL Cluster Manager installation directory, such as/var/opt/mcm
on Linux.In addition to the data files for all the clusters under the control of MySQL Cluster Manager, the data-folder also contains a
rep
directory in which mcmd configuration and metadata are kept. Normally, there is no need to interact with these directories beyond specifying the--data-folder
option; see exceptions in, for example, Section 4.8, “Restoring a MySQL Cluster Manager Agent with Data from Other Agents” and Section 4.7, “Backing Up and Restoring MySQL Cluster Manager Agents”.-
Command-Line Format --extra-config=file_name
Type File name Read this file after configuration files are read from either default locations or from the location specified by the
--config
option. Multiple--extra-config
options can be passed, and the files are loaded in the order they are specified. -
Type File name Default Value mcmd.log
Set the name of the file to write the log to. The default is
mcmd.log
, located in the same directory where the MySQL Cluster Manager installation directory is found. The location of this file can be overridden with thelogging_folder
option. -
Command-Line Format --help
mcmd
help output provides information on some file paths and all the program options; it also provides some usage examples of the mcmd command:$> mcmd --help MySQL Cluster Manager v8.0.39 on linux-glibc2.12 (64-bit) (MySQL Enterprise - Commercial) Copyright (c) 2007, 2024, Oracle and/or its affiliates. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Configuration read from the following files in the given order (enclosed in parentheses means not available for reading): (/opt/mcm8.0.39/bin/.././mcmd.conf) (/opt/mcm8.0.39/bin/.././mcmd.ini) (/home/johndoe/.mcmd.conf) (/home/johndoe/.mcmd.ini) Plugins Path: /opt/mcm8.0.39/lib/mysqlrouter Default Log Directory: /opt Default Persistent Data Directory: /opt/mcm_data Default Runtime State Directory: /opt # Usage mcmd (-?|--help) mcmd (-V|--version) mcmd [-B|--bootstrap] [-c|--config=<path>] [--core-file=[<0|1>]] [-d|--data-folder=<directory>] [-a|--extra-config=<path>] [-i|--initial] [--pid-file=<pidfile>] mcmd [--bind-port=<portnumber>] [--copy-port=<portnumber>] [--mcmd-user=<username>] [--xcom-port=<portnumber>] # Options -B, --bootstrap Bootstrap a MySQL Cluster using MySQL Cluster Manager -c <path>, --config <path> Only read configuration from given file. --core-file [ <0|1>] Write a core file if mcmd dies. -d <directory>, --data-folder <directory> Data directory for MySQL Cluster Manager. -a <path>, --extra-config <path> Read this file after configuration files are read from either default locations or from files specified by the --config option. -?, --help Display this help and exit. -i, --initial Reinitialize configuration metadata directory --pid-file <pidfile> Path and filename of pid file -V, --version Display version information and exit. --bind-port <portnumber> Portnumber to use for mcmd. [DEPRECATED] --copy-port <portnumber> Portnumber to use for file copying. [DEPRECATED] --mcmd-user <username> The username used to access MySQL Cluster Manager [DEPRECATED] --xcom-port <portnumber> Portnumber to use for XCOM. [DEPRECATED] # Examples Bootstrap a NDB cluster on localhost mcmd --bootstrap Bootstrap a NDB cluster with a specified mcm_data directory mcmd --bootstrap -d my_mcm_data Start mcmd with additional config file options on cmdline mcmd --logger.level=NOTE --mcmd.copy_port=12345
-
Command-Line Format --initial
After making a backup of the agent's configuration store (
mcm_data/rep/
) like thebackup agents
command would do for the local host, wipe the configuration store's contents before starting mcmd. The agent's configuration is then recovered from other agents. This is useful when an agent has fallen into an inconsistent state and cannot be properly restarted. -
Type Enumeration Default Value info
Valid Values fatal
system
error
warning
info
note
debug
Sets the
mcmd
log severity level. Possible values for this option and their descriptions are listed in Table 4.2, “MySQL Cluster Manager Agent Log Levels” in descending level of severity. When the option is set to a certain severity level, all events of that or higher levels are logged.info
is the default log level, and is the recommended setting for a production environment; running on a more severe log level produces fewer messages and makes it harder to trace a problem when it occurs.Table 4.2 MySQL Cluster Manager Agent Log Levels
Level of Severity Description fatal
Conditions that should be corrected immediately, such as a corrupted MySQL Cluster Manager data repository system
Informational messages about the product error
Conditions that should be corrected, such as configuration errors warning
Conditions that do not fail executions, but may require user attention info
Messages on main events of the site and from command execution (default) note
Informational messages to provide users with some execution details debug
Debugging messages that give execution details useful for developers. This causes large log files if used over a long period of time. While the setting of the
level
option is applied only to the host whose mcmd agent uses the option, thechange log-level
client command can be used to apply the logging level to an entire management site or to specific hosts. -
Type Directory name Default Value The parent directory of the MCM installation directory
Path to the mcmd log file directory. The default is the parent directory of the MySQL Cluster Manager installation directory.
-
Introduced 8.0.27 Type Integer Default Value 512
Minimum Value 1
Maximum Value 9223372036854775807
The maximum number of client connections to mcmd. Setting this option helps prevent mcmd from running out of file descriptors. This is similar to MySQL Server's max_connections system variable.
The default value is 512, and the option is set in the
[DEFAULT]
section of the configuration file. The option serves the following two purposes:
Sets the user password for an mcm client to connect to the mcmd agent with the user name set by
--mcmd-user
. If the option is not specified, the default value ofsuper
is used. If the option is specified with another value, the client must supply it using the--password
client option when trying to connect to the agent.Sets a password for the MySQL account to be used by the mcmd agent to access the SQL nodes. When an SQL node is initialized, the mcmd agent creates a new MySQL user account on it using the user name set by the
--mcmd-user
option and the password set by this option. See descriptions of--mcmd-user
for more details about the account.If the option is not specified, the default value of
super
is used.
The option can only be set in the
[mcmd]
section of configuration file, not on the command line.The option serves the following two purposes:
Sets the user name for an mcm client to connect to the mcmd agent. If the option is not specified, the default value of
mcmd
is used. If the option is specified with another value, the client must supply it using the--user
client option when trying to connect to the agent.The password for using this user name to connect to the agent is set with the
mcmd_password
option.Sets a user name for the MySQL account to be used by the mcmd agent to access the SQL nodes. When an SQL node is initialized, the mcmd agent creates a new MySQL user account on it using the user name set by the option and the password set by the
mcmd_password
option. This account is created with all privileges on the MySQL server including the granting of privileges. In other words, it is created as if you had executedGRANT ALL PRIVILEGES ON *.* ... WITH GRANT OPTION
in the mysql client. The existing MySQLroot
account is not altered in such cases, and the defaulttest
database is preserved.
If the option is not specified, the default value of
mcmd
is used.For release 8.0.30 and later: The command-line format of
--mcmd-user
has been deprecated. Use the format--mcmd.mcmd-user
instead (which takes precedence over all other ways to specify the option), or specify the option in the configuration file (both methods take precedence over the deprecated command-line format).-
Command-Line Format --pid-file=file_name
Type File name Default Value mcmd.pid
Set the name and path to a process ID (
.pid
) file. Not normally used or needed. This option is not supported on Windows systems. -
Type String Valid Values (Windows) consolelog
filelog
eventlog
Valid Values (Other) consolelog
filelog
syslog
The different logging methods used by mcmd.
Supported sink values are:
consolelog
,filelog
,eventlog
(on Windows only), andsyslog
(on Unix-based systems only). Use a comma-separated list to define multiple values. If you have multiple sinks defined, they can be customized under the corresponding sections of[syslog]
,[filelog]
, and[eventlog]
in the configuration file using thefilename
andlevel
options.Default value:
filelog
if thelogging_folder
option is not empty in the[DEFAULT]
section, andconsolelog
otherwise. -
Introduced 8.0.29 Type String Default Value error
Valid Values error
warning
Determines the behavior for handling unknown configuration options, such as those containing typos. Here are the values this option takes:
MySQL Cluster Manager versions before 8.0.29 ignore any unknown configuration options.
--version
,-V
Command-Line Format --version
Display version information and exit. Output may vary according to the MySQL Cluster Manager software version, operating platform, and versions of libraries used on your system, but should closely resemble what is shown here, with the first line of output containing the MySQL Cluster Manager release number:
$> mcmd --version MySQL Cluster Manager v8.0.39 on linux-glibc2.12 (64-bit) (MySQL Enterprise - Commercial)
-
Command-Line Format --xcom-port=#
(≤ 8.0.30)Type Numeric Default Value 18620
Minimum Value 1
Maximum Value 65535
Specify the XCOM port. The default in 18620.
For release 8.0.30 and later: The command-line format of
--xcom-port
has been deprecated. Use the format--mcmd.xcom-port
instead (which takes precedence over all other ways to specify the option), or specify the option in the configuration file (both methods take precedence over the deprecated command-line format).